Eye tracking is a methodology to measure a person's unconscious eye movements when they are interacting with a visual stimulus. With this method it is possible to gather metrics such as gaze points, blink rate and pupil dilatation. The data collected can provide us valuable information about an individual’s eye movement behavior.

Using eye tracking, you can answer many research questions: What is the most attractive visual element for people? What draws their attention? What they have difficulty understanding? How distracted they are?

Why and when to use eye tracking?

Around 70% of what we take in from our environment is visual. Through eye tracking, either in isolation or combined with other research methods, you can gather data about human behavior, attention and what motivates people's actions and decisions.

There is a direct correspondence between where people look and where they focus their attention. Our eyes have more than 2 million working parts, 107 million light sensitive cells and process only a very small area, which means eye tracking can provide a precise measurement of where a person is looking.

Eye tracking enables connecting qualitative and quantitative research by actually seeing where participants look, which allows researchers to implement the technology for various purposes such as academic research, healthcare, psychology and psycholinguistics studies, market research, marketing and product design, amongst many other academic and commercial purposes.

Imagine your company is releasing a new product and needs to advertise it with a digital campaign. With eye tracking, it is possible to conduct an A/B test to find out how much attention the branding receives in different layouts. Eye tracking can also be used in UX testing to establish if people are overlooking a certain screen element or they see it, but it is not clear how they should interact with the button, text or image.

The science behind it

The history of eye tracking started back in the late 1800s, when studies were made using direct observations and Louis Émile Javal identified that our eyes don't sweep smoothly through a text, but rather take short stops. Other eye tracking devices were developed and studies were conducted, but it wasn't until the 1970s that eye tracking research became more popular and started being used in the market research industry.

For researchers, the metrics of fixation and saccades can already offer plenty of information regarding the gazing path of the participant. Fixation is the state between saccades, when the eye remains still over a period of time, for example, when the eye temporarily stops during reading. These breaks are brief, anywhere from tens of milliseconds up to several seconds. During fixations visual information is processed and it is possible to see where attention is. These insights can be really valuable for applied research.

Saccades are the rapid motion of the eye from one point to another between fi (e.g. from word to word in reading). They do not always have simple linear trajectories, instead, they can undergo one of different shapes and curvatures. Saccades are important for fundamental research but not so relevant for applied research because no visual information is taken in during saccades.

Thanks to the technological advances we have had in the last years, researchers have now a better understanding of how the human's visual system works. In the last years, the process of measuring the eye movement became more accessible and now are widely used for several purposes.

Eye tracking methods

For a long time, conducting eye tracking research was a costly and difficult process, since it involved expensive equipment and lab settings. Nowadays, there are better options in the market to conduct an eye tracking research with quality and precision that does not require a significant financial investment.

The available technologies today are both researcher and user friendly, including wearable devices and smartphone solutions. Wearables are glasses with built-in camera for the participants to wear and track the eye movement. Although this eye tracker enables the technology to be used in different settings, it is very expensive to implement and requires every participant to have a special device in order to participate in the study.

Thanks to recent technological advances and machine learning, it is now possible to measure eye tracking with webcam and selfie cameras from computers and smartphones - those are software-only solutions that almost everyone has easy access at home. With this method you can test websites, digital ads, videos, apps and any other digital product in the participant's natural environment or in-lab, if you still prefer to conduct research in person. Combining eye tracking measures with behavioral and subjective methods can be a powerful strategy to gain insights into people's attention, opinion and behavior.